Hello all, I've seen this asked a long time ago here but I could not find an answer, so trying again. I realise this is the old way of putting a call on hold, but why does sofiasip automatically change my origin and media IPs? When the address is "0.0.0.0", sofia sip changes it silently, after calling "soa_check_sdp_connection" from "offer_answer_step", while processing the o= and c= fields before sending the INVITE. I am just wondering why does "soa_check_sdp_connection" check for "0.0.0.0" as invalid, when some systems out there still use this address to signal that the call is on hold: int soa_check_sdp_connection(sdp_connection_t const *c) { return c != NULL && c->c_nettype &&c->c_address && strcmp(c->c_address, "") && strcmp(c->c_address, "0.0.0.0") && strcmp(c->c_address, "::"); } Thanks, Kun-Yao Huang